Broaching machine



Filed Ndv. 11, 1929 2 Sheets-Sheet 2 Patented Nov. 17, 1931 PATENT OFFICE FRANCIS J. LAIOINTE, OF ANN ARBOR, MICHIGAN BROACHING MACHINE .Application filed November 11, 1929. Serial No. 406,261.

My invention has for its object to produce a broaching machine wherein the broach is held stationary by the stationary cross head and the work is moved hydraulically along 5' the broach whereby'the cutting action of the teeth of the broach may be readily observed, and the efiiciency of the machine is increased. In the preferred form of construction, the hydraulic pressure means is located at a 1 point above the working plate and the cross head, which gives free access to the work by the operator of the broaching machine. Also, suitable means is provided for controlling the supply of liquid under pressure to the hydraulically operated means.

The invention may be contained in machines that vary in their details of construction and, to illustrate a practical application of the invention, I have selected a broaching machine embodying the invention as an example of the various structures that contain the invention and shall describe the broaching machine selected hereinafter. The

broaching machine referred to is shown in the accompanying drawings.

Fig. 1 illustrates a front view of the broaching machine embodying the invention. Fig.

2 illustrates a side view of the machine shown in Fig. 1. Fig. 3 illustrates a view of a piston and a section of one of the cylinders used to operate the working plate. Fig. 4 is a side view of the valve controlling mechanism. Fig. 5 illustrates a view of a section through the valve that controls the flow of the liquid to and from the cylinders used to operate the work plate.

The machine is provided with a base 1 to which is rigidly connected the four standards 2. The standards 2 are also rigidly connected together by-means of the cross head 3 and the top plate 4. They extend through the corners of the cross head 3 and the top plate 4. This produces an exceedingly rigid construction for holding the parts of the machine in position and for guiding the movements of the work plate 5.

The standards extend through the plate 5. It is connected to a pair of piston rods that extend into the cylinders 11 and are connected to the pistons 12. The piston rods 10 trolled by a pair of levers 30 and 31. The

have a diameter that is nearly that of the interior of the diameter of the cylinders 11 whereby the return stroke of the pistons will be accomplished in a very short interval of time, assuming the same volume of delivery 56 of the liquid to the cylinder during the return stroke that is delivered to the cylinder during the working stroke.

The cylinders are secured in the cross head 3 and also to the top plate 4, and thus the 60 cylinders 11 will be rigidly connected to the standards 2. The piston rods 10 extend through suitable packing rings 15 and are connected to the work plate 5 which is moved by the pistons along the standards 2. Each cylinder is connected at one end by a pipe 16 and at the other end by a pipe 17 to a controlling valve 18 which is adapted to connect one or the other of the pipes 16 or 17 with a source of supply of liquid, such as oil, under pressure through the pipe 19 or to the return pipe 20 of said source. Ninety degree rotation of the valve 18 reverses the direction of the fiow in the pipes 16 and 17 whereby the pistons 12 may be reciprocally moved in the cylinders 11. Since the volume of supply per unit of time is substantially the same and the cross sectional effective area of pressure 011 the pistons 12 is substantially equal to the entire area of the piston during the working stroke, and is equal to that of the piston less the crosssectional area of the piston rod, the piston will move rapidly during the return stroke and slower during the working stroke.

The breach is connected to the cross head 85 3 by any suitable means. It extends through the work plate 5. The work is placed on the under surface of the work plate 5 and as the work plate 5 is moved by the operation of the pistons, the work, such as the member 26, is moved over the broach 25 until it passes the lower end of the broach. The work 26 is thus delivered from the end of the broach 25 at a point near the base 1. The work 26 may then he dropped from the broach 25 and 95 allowedto fall a short distance or may be allowed to pass to any suitable trough or guideway for directing the work to one side.

The movement of the work plate 5 is conlever 30 is conveniently located for operating the lever manually, while the lever 31 is located where it may be conveniently operated as a pedal lever. Assuming the work plate 5 to be located at the upper end of its stroke, the lever 30 or the pedal lever 31 may be operated so. as to establish connection between the supply pipe 19 and the pipe 16 and the return pipe with the pipe 17. The pistons 12 will thus move the work plate 5 down forcing the work along the broach 25. The valve 18 is again operated to reverse the connection as between the pipes 17 and 19 and the pipes 16 and 20. This is done automatically by means of a rod 35 having adjustable collars or stops 36 and an ear 37 located on the Work plate 5 and slidably movable along the rod 35 and so as to engage oneor the other of the collars 36 at points in the movement of the work plate 5 dependent upon the adjusted positions of the collars 36. When, therefore, the rod 35 is pulled downward at the completion of the operation of the work plate 5., the

rodi35, which is connected to'the lever 30,

causes the movement of the link 38 by which the lever is connected to the valve 18. The link 38 is connected by means of a crank 39 to the rotatable valve member 18. The crank 39 is turned so as to connect the pipe 16 with the return pipe 20 and the supply pipe 19 with the pipe 17 which causes the return of the work plate 5. Preferably, the upper collar 36 on the rod is so located with respect to the rod 35 that when the ear 37 engages it, the valve willbe moved at an intermediate position to stop the flow of the liquid to the cylinders and, hence, the cylinders will be brought to a standstill. In the downward stroke, there is suflicient momentum of the piston and the work plate 5 to cause the work plate 5 to move the rod 35 a sufficient distance that the valve 18 will complete its reversal of connection, while during the movement of the work plate 5, the work plate 5 is brought to a stop either by coming in contact with the ends of the cylinders to sufiiciently prevent such movement of the work plate5, or the upper stop is located at such a point that the momentum of the parts connected to the work plate will be absorbed by friction to prevent the reversal of the connections by the operation of the valve 18. lVhen, therefore, it is V desired to produce the working stroke of the Work plate 5, the lever 30 or the lever 31 is operated to further rotate the valve 18 to complete the movement of the valve and establish the connections as described.

I claim:

. In a broaching machine, a base, a pair of cross plates, three or more standards secured to the base and to the cross plates, one of the cross plates connected to the upper ends of the standards and the other connected to the standards at points intermediate the base and the upper ends of the standards, a broach connected to the plate located intermediate the base and the upper ends of the standards, a pair of cylinders secured to the cross lates, a pair of pistons located in the cylin ers, a work plate connected to the pistons and located below the cylinders and movable along the broach, the standards extending through the work plate for guiding the work plate, a valve for controlling the movements of the pistons for producing reciprocatory movements of the pistons in the cylinders and reciprocatory movements of the work plate along the standards and the broach.

In witness whereof I have hereunto signed my name to this specification.

FRANCIS J. LAPOINTE. 

